Telephony.



M. L, JOHNSN.

TELEPHONY.

APPLICATIM FILED :du 5,1913.

Fat-@mmm i, will 10 SHEETS-*SHEET 1.

N'V'ETB,

Jax-msm HTNESSE 1L f N M j T i A WITNEC SES EL ZT M. L. JOHNSON.

TELEPHONY.

APPLICATION FILED MAY 5.1913l 1,1 19,355. Patented De0.1,1914.

10 SHEETS-SH EET 5.

. ATTORNEY M. L. JOHNSON.

TELEPHONY.

APPLICATION FILED MAY 5. W13.

Patented Deo. 1. 1914.

RTH EX. MAIN EX.

E2 a /22 75o f 4mm/m9 m @PX 'f U' ATTORNEY M. L. JOHNSON.

TELEPHONY.

APPLICATION FILED MAY 5.1913.

1,1 19,355. Patented De0.1,1914.

10 SHEETS SHEET 7.

251125 24 l@ aen/Q1 BY ff' f ATTORNEY M. L. JOHNSON.

TELEPHONY.

APPLXUATIOH IILED MAY 5,1913.

Patented D90. 1, 1814,

l0 SHEE'LS SKULL'. 5.

/f Y WWW/1.0 77W @0 y AT T 0 )KN E 1" M L. JQHNS'ON.

YELEPHONY.

APPLICATION FILED MAY 5.1913. 1,1 19,355, Patented De.1,1914.

10 SHEETSY SHEET EO` NORTON JOHNSON UNITED OFFICE.

MORTON L. JOHNSON, l?" "TTECAG-O, ILLL'YSL, :iESG-NR. BY MESNE ASSIGNMENTS, T()

FRANK E. CQQK COMPz-y TELETHNY.

Application filed May lii To all 11i/'min if In /11/ munir/1 le it known that l. lllon'rox li. Jonsson. citiuen ol' the llnitecl States resi/linx? thicago, in the county ois x(ooi. and tatr ol'I Illinois.y have invented a certain new and useful Improvement in 'IfelephonyL of which the following is a. full.y clear.` concise. and exact description, reference beingl had to the accmnpanying drawings. forming a part of this specification.

My invention relates to telephone exchange systems and has for its main object the provision of link connectors having an answering telephone line extension section and a plurality of connecting ends or telephone line extensions whereby an operator, after having el'l'ected connection with a calling line. may extend such calling line into connection with any telephone line extending to the other switching sections to which said connecting ends are individual without lisarranging the connection with the calling line.

ln the preferred embodiment ot' the invention the second telephone line extensions common to the first terminate in ts oi' wipers of an electro-magnetic switch and each of these Sets of wipers is provided with a plurality of sets ot' waiting contacts con stitutiug terminals of a set oi" ad ifonal telephone line extensions. each set oi' additional telephone line extensions extenillii'rfr to a di lferent switching sei'ftion.

l will explain my invention more fully by reference to the accompanying drawings illustrating the foregoing and other features or' my in rention and which drawings illusg. trate the preferred embodiment of the inrention.

ln tin drawings Figures l and if. taken '-ollectivelv with the conductors at the lett hand ol' Fig, 2 in al'inenierit with the foniluctors at thc iight hand ol Fig. l.. indicate the general plan ol' a system equipped in accordance with the invention; and Figs. lo lu. laken in consecutive order. together illustrate one embodiment ot my ini'ention as it has been practiced. substantially Referring lirst to Figs. l and taken collectirelv. l have there diagraini'natically outlined a telephoin` exchange system. two subscribers` substations 2.30 and 290 being indicated. the lines Jfrom these Substations extending to an exchange where each is prmided with multiple jacks 1 distributed Specicatien of Letters Patent.

Patented Dec. 1, 1914.

Serial No. 765,583.

.nnong diiiereut sections of a manual s\\'itf;.hlie-ard at one exUiange. lf/icl'i sub, :rihefs line proridel with a plurali i-'iul'tiidi nate/l sets of cor-.tarts t?. tl" o( waitin` winlacts pertaining: to cach line lieing distributed anioiig calling line lindei' switches each iinder switch having ay set ol waiting contacts L) peitaining to cach of the lines. ln practicing the invention the subscribers telephone lilies are desirably divided into groups. fifty lires per group, each group having live calling line finder switches A, each finder switch having ifty sets of waiting contacts 2, each set oi waiting contacts pertaining to a different tele.- phone line of the group of fifty. I provide a group oi', say t.'\'ei'ity-iive, calling telephone line extensions 3 for each collection o' ten groups of subscribers lines, that is each group of twenty-tive calling line extensions 3 is individual to each larger group of five hundred subscribers lines. Each calling line extension 3 is provided with a plurality of rifiultiplyy related sets ol contacts l. ach set of waiting contacts l pertaining to each callin(r line extension beincluded in a calling line-extensii'in selector switch B. euch selector switch hay ing' a set of waiting contacts i pertaining' to each calling line extension. (luc calling line extension selector switch B is shown as lieiug individual to each calling line inder `switch A so that each calling line extension il has a set oi' waiting contacts l in each of lil'ty switches l. When a call is initiated lne calling subscriber. as a consequence of the ren'mval of his receiver from its switch hook. energizes a line relay 5 to close the circuit o'f relay 0 common to the group of lilly lines in which the calling line is inrluded. the relay (3 closing' the. circuit of a driving' magnet oii the switch which hap pens to lio associ-.lied with the calling line liv means of the master switch C provided with waiting contacts individual to the dii"N lerrizi sw itches in the group ol l'il'ty lines. the wipers of the switch C being couunon to the lines of this` group and norinall)v rest ing upon a set. ol i-.raiting contactsy pertain ingi'o some idle l witch A. The wipersl of the su itchcs .i normally rest upon waiting contacts belonging to the. telephone linesv and. of eourec. are not stepped 0H oi' such con tacts when the engaffed contacts pcrtaii'iing to the calling lines are engaged by the irl ill liu ,un L individua! tu iin o) fi is wt in ini/dim. in inn! 1m 1. Mii@ vf iii Miri; i livin pivnwmiii by :a Uiirii Swiifii 'if Inwing unit il which pinmin tu trunk lino, unainnz" M ixrwlirig to :mii/ing carinii-ir; l inifiiLMC in aizirririe I" that ari', inriividinii in irnni: .Einw 'axtemfi to vfriiiing fontrwts L of svntfiir-:f G inmitmi in zinothvr n wlmn'i. whore Hwy muy be )p;.^zii. vi to bring :ai iinu ciiniiingf 'in the iziii'srwmnm imnnzcfim'i with :in iiiie iiw'nolf-,piuma @ety i) by way uf the switvhew IV und Y.. but, one switch in 9:2011 of the tu() grmips D, D. E belonging lo 'uch operator living of service at :i time. to extend thv 0pm'- :itnr'by tcloplmno (-minmiion, the 0l01n0ns 8 :1mi 10 performing the funi-,Hons in mincirtion with auch sot of thro@ witches D, D, E :is izithm'to describvd so that if one Switch D or E (if one srt has extended tho connection of the opeiutors telephone :i Switch D 0r E in the ('Qmpnnion Set muy be in rendinws to extend Simi.: connection when the first enr .taining to idle iriieea ployed switch has been released. l timing; device 16 is individual to each ope-*alors telephone line and when 'an operai tele phone has had its connection extenoi l yond the predetermined period of tine; they element 16 will operate to displa\v a signal at 17 viihich may he in the presenee olla sirervisory operator.

vhen the calling suhseriher has seleited the telephone equipment t of an itil;l epm ator, the operator is intornnd of l aun-n ber of the line desired hy the ealhnff suit scriher and the selected opviator will et :i switch H into ope 'ation to extend the ralling line extension connertetl nitl: the ealling line into connection with the link reir nector which is to he employed liv the operator in extending the calliin,y line into 5onneotion with the desired line. lt' the tit ireal line extends to the saine exrhangle wi the calling line the operator will emploi' a link connector having a eonnerting ilng '1H which' the operator will insert in the jark l. of the desired line. If the desired line tends to another exchange the operator will employ a link connector lnrfiug a selet'ior switch G1 companion to thtA .switvli lil and which selector switch will extend sui-h link connertor into connection with eonrluctors extending to the other exeliangie where the connection .between the calling: and desired lines is finally eifefted. The link connectors to be employed are desirably automatically predetermined by selector switches 19 coin-- inon to the link connertors of enel kind at, eaoh operators position. These selector switches 19 automatirallyv tiring their wipers into engagement with Waiting contacts pri link connectors and oreasion the operation of signal devices "2O individual to the link connectors that have heer .-;ut-:- matirully selected hy the selertor snitoh llt The operator thus appropriares tor ilse onli those link connectors of the kind desired in Corneet ion with Whirh n signal lamp Q2u glows. lllaeh selector suitcl: (il is ill trated as having four sets ot' wipers liant ing inixed planes or levels, the waiting eontaf'tfl of each level belonging;i

to telephoin` line extensions extending to different open ators positions at the saine or dil/Fermat exchanges, similarly positioned wailing! routants in the various switrhes (-l of" the litiferent operators loeing;- i'uiitiplefl whereby any operator may have access to 'vai-ions positions that the sWitrht-s (il are de to reach. ln the example rhown tour of wipers are illustrated for enf-h :,wirh tl. they uppermost set of wipers heine; designed for extending calling lines (250l Q), ex tending to the south exchange, to the main exchange. the next set of wipers serving to egttend the calling lines to the information operators position indicated at, 2l, the nest. set of Wipers extending the ,lines to :i toll operatori position and the liottom set oi" vipera en r ding the calling linee; to the north wrliarirli. The tour sets of wipers thus ifeiietitute a group of connecting terminnls which are common to a single link connector having a Compleinentzil end common to the connectingr ends of the link eonneotor for eouneetion with the CallingI lines and while the operator is provided Witl' equipv nient fr liringiug the link Connertors into ronneriiun with Calling lines hy her own iullil he 'IIT-finition is not thus to he limited :iu-fl nhlr the mulripled eonneriiug ends oi' each link foiaiwetor are in the form of traveling wipers lieltinging: to eleotioanagnetic switrhw. the invention is not thus to he limited. A plurality of sets ol waiting;r mutatis :ire prrr-.idoli for each set, of wipersthese uniting; fontucts constitutingir termi-- nfil1-` ol additional telephone line ekteisioiu'Y n'hirli extend to u ililuralit)v ot su'itrhiugg soot ions.

lt is'usuully necessary to be allie to limit the coniersation to two eonnected stations to whirh end the operator is provided with switrhing nierlnrnisni 22 individual to each set ot' wipers 'for alone bringing' such set of rfipere into the established. telephonie Cirfuit, the reinainin(r sets of vipers being exeluded from telephonie oonnertion owingr to the idle condition of the switches 22 individual thereto. There is thus provided a telephone exchange system inthuling telepiloot lines extending to on(` suitehing se(- tion` telephone lines extending to other si Lthlng' motions. and :i link eouuertor in` terreni 1;; hetu'rrn the first suitrhingser tion .and the other switeliing sertious, said link 'onimtor ufluding u telephone line extension for roni'iertion with u telephone lize extending to the first switching set'tion. am? t: telf-phone line extension for euch oi' ihr seeonfil swirl-hing sertions for extendingr the telephone lines extendingr thereto. the tirst telt-phone lintl extension lie-ing eoinuion to the fitter Winphone lint extensions and the latter telephone line extensions heilig in permanent iiia'fit relation with the former. ln the cirlmliiiieiit oi the invention illustrated these letter telephoiuline extensions te ie in wipers and while these wiper:- tu mlm-:sions eonnerted therewith are ;r.,t`ei'al1-l r iz. pernninent rire-uit, relation with the iii-st telephone line. extension the invention is not to he limited to such :i fliarurteii.-tir as l lielieio it to he lirondly izrv with nie to provide :in elm'tro-iinijjuetit' suite-i; :Mapu-fl to ronnert one su'itif'hiugr :zertion with n plurality ot' other switching sections hy means oi' a single line eXtension that nii-ty he interrhangeuhly associated with the wipers lt the culling subscriber' should desire eonnertion with a subscriber whose line ex-. ten/ls te the main exchange the topmost llfi ' trnnli U1 torni-i., ztinfi' ifi il," A :in iilliifelcciior switch A[V1 pri-ivrzxhly locntcii in the niiiin whining@ Thr imitan F1 will thoriupnn opcrnte to conncft. thc trunk M1 with :in idle trunk, extension 121. thc trnnlt i:xl;cii,iliiis 121 lining nonnnntntl with waiting contacts in itchns E1, those trunk extensions 1:21 boing iii'ipnrtinnnfl :inning thiL operntorfi punitions having telo phone eqtiipinnnt 91, tho 'wipers ot' the. Switches l `1 normally resting in connection with waiting contacts belonging to idle trunk liuc extensions 121 whereby an operatingr switch F1 will utonniticallybring the \\'i1iting idle operator into connci'ition with the, calling subscriber. The calling sul srribor will inform the operator having thc` snlcutcd equipment 91 otl the nuniber of the desired line und this operator will insert u. plugy 181 into the Spring jack 11 of tl1 de sircd line and will also set the Wipers of the Switch H1 individu-ul 't0 the plug 181 to bring these vfipcrs into connection with waiting contacts bclonging to the employed trunk line cxtcnnion 121. l'lqnipmcnt :it und pen taining to thc nniin exchange includes :ipp-irzitns which is similar to oqnipnicnt zit :infl pertaining, to the south exchange. The equipment at and pertaining to the inuin exchange which is Similar in function :unil Operation to the equipment :ity unil pcrtnining to tho sontfh exi-hnge is given similar rlmrnctcrs of rcfcrcnce with thc :nlilition ol1 prin'io nmrks :is nxiioncnts, it being thereby inincrrssnry to r-'Jpcnt the dvscription of thc ogcrntion ot thc ciniipincnt :it :intl pnrtzliw ing to tlnI niuin etclmngc,` itlining only rcY rgnirctl to :st-Ato that the uppcr switches n :it mich opcrntors position :it thel ninin clmngg'i: nrc cmploycil to connifct :i nniin chungo culling? Snlm'rilnrr with :i south i'lizxnygc cnllcfl xnhSci-ilicr.

Hott-ronca will now li; niznln more partici lnrl)v to ViQfS. C3 to itl inclusive for ii nniri"y ilchiil lvfrription ot' thc, nncraition nl' the toni. A. -inniing that tho Subscriber zit. stir tion 250 ilinzircs connnnnication with ii-'silhsrribcr :it sitntion 390 thc lines of then@ two stations c.n.t-;-rinj1V thc, saine exchange. The culling' snlilcrilicr will rcniovc hin` tclhpiiono rcrcircr from itl Switch hooi; Lil 'whcieby the Switch hook is rninowd from its; norinfil Contacty thnt, norninllv inclnilw thc hell 25 21ml thc comlcnsor 126 in lniilgo ot the inlophonc lino, such switch thereupon engaging its nltcrnsitc. contact to inclnilo thi` tclcphoncy tlj;.ii. li1ittcr '27 :it thc culling station in hriilgo of the culling line. When this bridge is ostnhlishcfl u circuit is closcil which is truco :iblc from thogrountlcil common buttery Qt, tho rcliiy 5, the lower nincling ot' the cntotl" relay 29, the armature switch of this reo grammi@ l f wh u 'j ihn Jr-fo coils` nl il ufl-ny ll :infi tiitfcirntinl, The rcliiy n circuit triiccnlilc 'from the gi'ciinti, buttery 25, through tlic roliiy t?, (common to :i group of iiftiy lines) the iirinzitnri: :fnii/rh olf rclziy 5 intl its thon engzrgcd connic ih thm grounded linej signal tt. tho i l mls El?) not lining nfci'l h v ihn opixrfitors in thc normal operation ol' the r-xriizil'igc, lining Liri-cli' pri'rriclvil to innlirlito trouble :inni for m'crlllow cailles. The gronnihil rinntnrn switch ot' whiff t5 first. csizihliilws n circuit trziocnblc i'roin this inxitcli, tlxn cnnzlct, tlicrcot' inn'i'icrlintely :nljnccnt thcret-f), tho slnggihly opornting rinny 3l.. thc lowor iirnnitnre switch ot the` :ilngfgishly oljicrnting rclziy 'lil :mil its normally cngiigml Contact, the wiper 213 of lnzlstir Switch (l common to r. group nl liity lincs, thc Whiting contact with which thifi` wiper 'il lmnprns to lio connccted (the wipers of ih@ switch C being nornnill \Y conncctcil with Waiting contacts pertaining to Sonie nnrnnjloycil Sz'vitoh A), tho wiper 3l ol the Switch tlnit hziiprns to be zissociiitiil with the Switch t, the n niting Contact cng'nn'cil hy thv wipt-r Il rml,

manning Vor oncy cxzinnile ilnit thi: r :ailing contnct engngcil by thc wiper 3l pertains to the culling lin@r` th:` nrinzltnrc, switch nf reln)r 5 ot' thv cullingv linc und its fntjnnjml contnclg thc rrlfiy t3, t hc grnnnilnfl lnittorjy' 1"" stfnnning; tor :in-oth euiiiliic. that thc "finer .ll loofnot lnipprn to lic :fonncctcrl ith thcrmllinglinthoncircnii onlill'ioopen :it thi; rcliiyi" fi pnrtiningg to thc nonciilling: lince with which the switch is connai-tml :imi over whose contacts, thi,x 'wipcrs ot' thiS switch nn v png-;, tho n ipnrs of thc- :4 itch A lining; (lrivrnfto snel; the ifontsictfs of this ciilling; linie hy thc poration ol the) riiicliret nlmcl iii set into oignriiti-'m lq. the motor 'nrt liti, thifs motor ii'izignc .i lifnl oiwriitinj; rclzij: 37, the nrnifitnrc Swit this rclriy, thu Contact cnfijzigfeil tlwruliiy, tho urnifiturc switch oi: rclziy 218 (Whose circuit is thc second lo lic cstnlilielicrl liv thc rllziy at. thc Contact scronil to lic cf'iifzijjcil by 'thc :irnnxtnrv switch il1 r-wlny t isi the :irnniinrc switch ni rrlrrv 3f?, thc iinpcr nrnmtnrc Snitch ot' rcluy 3i :mijl its Qng'ngvd Contact, ihnv ivy/por nrn'nitnro switch nl" rlny 32 and itry cngzigml contati. thcl wiper 2li? of switch (la thc, rfiiiiV` Contact happening to be ongngcrl h v thiwiper, to thc grounded motor mnifnot 3h.

'llhe relay 37 is a circuitintnrrnptingr reliiy to intnrrnpt the ciw-,nit iuqt, trziffciil from the motor nmttnct 3G .rlwrnhy tho ratchet wheel is stepped around until the Win91' 34 engages the Waiting contact; pmtfiining iliccofitict nelnv :mel

www. il

f* mlm il il lll lowcnmmt nomma/l Contact of tl'liS armature Switch, the moto!t mllgmf, .'33 of switch B lmliviffllml to ill# Ompluyf-ll ,w'lfvl'x A; tho :unmture switch nl the f'lwut intm'r'lmtlg relai] il mul the Contact nl' (his nlumture switch, to the freunde-l l l The motor' magnet 53 la, thu@y @per-:lim lo move the ratchet Wheel 53,53 that. n'mvfs the wipers of the switch B until ille wip@ fili engager@ a grounded Wait ing Contact pertaining to one of the four sllnmlf; nl m mwmplnyell vulling line eX- lglfiwwn mmf'atoll with nn Unomlavtm switch l):

mf of ill Y PHN" upm

uw 1 @mun t simili Etf) thc 1' and ummm 5in' pcltiainng tv iin@ "hes in the up of' x containing the vm- :um' the reuy 8 common ground from ik@ w mtl-'.1 i

.a emma a nim"- fil) armature swiich of slug" Y Y of one thousand ohms Le 'i l i iwimanie ol' the upper Winding of of relay lo the gmundwl laillery `r I 1 :Vif tvc() hundred fifty nlmis. relay TT is under the calling a' n the previously partially energized control S0 as to prevent the are i3-il is fxiirripletely energized upon the operating lie relay 75 l'aiiliily. siii-tary engagement wi tlm arn'iatiire 0l' T5 establishes a, locking airmail: sin: iii-fsw." magnet Si with its cnntavt, the timetable from the. lefbharidf alimentare ,Switches 0l' the relay 8f3 are at ture witch immediately adl i, Qliy the circuit in the, autor ing ol this relay, winding iii' relay nl i1. npened at lie right hand wir winding of relay 7l?, 'alle lcll. liana iin* .ff-vond from the limtoni armasvvitch of relay TT and ilA ma@ nel: nl' relay S3 0 that ille wipers of grounded battery Hw 1;. El mmm t wat 'm tiolled relay 7G tln'ireul'mn wataifiiw flie ailing line eXtenSion 3 traceable from the grounded iaia'nr eingdifiyezl erwin l calli! l. lier has Connected arinatin'e Muizen ol relay iii and il 'iis- The relay 83 eistalilislieS a Contact the bottonnnost arn'ialinv mi infr fia' Piselli traceable frrnn the lille emliluyed relaiY 1U and ite'. i if@ 'lV-1y ,l ila upper Winding 0f lacl, tlie lf'lly hand armature inleixf'iiediae armature switvll lay (22 and ila engaged miliari im 1 :my :lie npprnniet Contact of this TU of the employed wfiluli l). lli/q mining;- mi'ilcli, the wiper 8G, of the Switch Contact engaged by this wiper` Elie winlng of rela)v lfi. tothe wailing' Nadal/ lfm' alle wipvi; SU pertaining tu tlm paniun to the, en'iploeil pl i tainingr to the 'ailing line viti-miam nal; the calling subscriber line levied and (xa:-

lay 78 and iii-1. engaged minimal. t'

:sain-lu tlm interniediaie armature switch of' nected Willi his line llirmigli iie agency of relay ifi and its cimtaeft. m ground. Relay switches A and l5. eirenit. ih esald ivd is' which wa@ energized when relay 83 was for Vthe motor magnet #l ai' die :nuten il une! d has a lnuking circuit established balla l'fn itself tr @Cable from the grounded lia?- liii-.i' *5h lll-s; ri li liand armature switch (if zraiealile frmn'tlie grounded rirenit inerriqiling relai' w'ilcli of this relay 5i,

air-:er Contact nf this armature 25].y the next Millie limiti f, afina! :i wifding el' relay 15, the wiper relay h3, ln right l :ad 1mi( '1li Vll and ille intact engaged arinatnre miirli, lplie wiper mi il inner mail of the intermepluyed switrh l1), and tlie ciifiau 'i' relay N3, and tlie thereby the, amici' intact of il armature switch, lo grounded armature sivitili tu lii la; nl tmf wipe;- Sl. The lari'- rrualin' switm n" relai.' Si?, leaves its` il #anni and engagea its alternati, malta-yt L0 ixdallisli a :fircnit trav alilclrmn grfiixfii tlnnnggli Said armanre switch. lal :ilernav inta-t then-ifi'.y tlie wiper Si' nf the tcll le", the right liand armature swisl wf relay I5 and its crmlait, tlie niotirr magnet 01' the Snitch 15%y the vircnit iiitlie vinding 0'1" relay 7S, this ai Am'it'wli, to Aaground. Yllie wipers of tin I-l will autnmatically turn until the 8U engages lli@ waiting contact to the eti-and of tlie calling sul "Vilu pertaining ril) r levied willing line exteneiun 3 wl'iiuii is; wir

in-wtvd diri-elly will] grown l ybaticvry allie armaturii swieli 0i' relay T6 Llirmigl'i relay (ai and is free from direct gitanid. when izlie v.' iper Sleing'agus tli iS wa i ting can act a cire!! it is minima-d from llie mili in' l and rifiizifft le tlie frmunled battery wir I" 'afiewil ii passing lliat .'lie rela)Y eniigizeil owing Le tlie i by liu: rela k raiea'nle l amer) the right wf this` relay, .flie npainiaare awiteh, the i the wailing con- :ITA

ready lo operai@ liy a n nu; ti` bia wiper, the motor maliv the wound grounded i rinaiin'e sinfsi lh 'elle Circuit' inferrnpting el'l nl' (lie winding' il relay 27a the mi its armature siviteli and vwnl'ail'id this arnmuri '1w-nimh ille mnh ii'lzerelrv the circuit of iipffnffd ai tlie wiper (il 0l tlm 'nlerinfaliate armature lai #rif opening dax vii-unil if ,it hand armature Swiufli nl' Elie Cirvuil 0l' the einpli'iycd Srl and the -miiav engaged llaa-ilu. tu ille bottoni arinaizre #wils and tlie lel' hand Connunl" switch the rieiblganie 5&5, tllie i1' of relay to the ground` pting relay 85), by way nl itsl arniailure' 1 lli) the

fland ma@ C hmm 274.

tu Hm v, u@ n la ulfscrwerfs cumff @mute Qgnmct., the te1eat jn, called staresstnnee compared the bel bridge), the

Vinny ZJ mal 12" of allied line, to the upper of the caed line cutoff ma, which muld not "De @Ik 1 n1 'mu Wuxi Vi i "K neig' iiilfiil #mmm-thin willi lli@ liiii.

l lll# Vin i im,

relay 98 is ivrolmi Switch liOOli'. thi iiiiiiiitilfc. w, il, am? 1lii iiiipmi i'iflif: irrilgv ilf iiiicwiiuii Quei-nid l; li'wiii 'liif tip :unl mam# 1F wi tlifx. Miiil 'if/lil; iiiliiiiit prvwistiig t. f mil 2() in will iii nim-iii. plugs n iii ini-ls lmlfling: the :ifciii'wiiiel culli'il iiiwii im L xml 'iii ii i l Hiirlff lwl l'. miv.

f ihr-1% unwilling l this? line. 'when rallingin elleeting its extension, circuit continuing Vfrom this wiper 48, hrimgh the winding of relay 45, the armature switch oiA this relay and' its contact` to thisl grounded battery 18. Thus whether the chaired line was a preiii-usly calling line or a prei ions-ly called line the relay 91 is ener` fixed `to open the circuit ot relay 95 and to edabhsh the locking circuit of relay 91 traceabie irom the lower grounded arn'iature switch of relay 833. the alternate contact ol il Es switch. the intcrn'iediate armature switch of relay 91, the alternate contact of this switch. the lon er winding of relay 9i, to the grounded battervy 28. rl`he circuit for relay Q5 is opened at the normal contact of the intcrniealiatc armature switch of relay ill to leave the plug 18 inserted in the jack of the iflesireil line. 'l'ree of bridge connection. The calling subscriber will know that the desired line is busy onlin; to the establishment i f a busy tone test d ie to the interr\up tion of a primary circuit that includes an inducing winding 111, the armature switch next above the bottom arn'iature switch of relay 971, the `grounded interrupter relay 112 and the armature switch and its contact beincr desirably connected with a condenser 113. 'l`he induced winding 111 has its terminals in the contacts for the two upper armature switches o1 the relay 5)1 whereby the induced winding is included in bridge of the talking conductors extending to the calling station by apparent connections whereby the calling subscriber will receive the test and upon placing his receiver upon its switch hook` will reirlcr ther equipment idle which' intervenes between the calling station and the plug 18.

1f a plug 18 happens to be in the jack of a wanted line at the operators section of the board and another plug 18 has been designated for the use of this operator, such operator will apply the tip of the second plug t0 the slee\e of the first plug and fully depress the, key 115 that is individual to the plug being applied whereby an audible test signal is conveyed to both operator and calling subscriber if the line tested is busy, the absence of such signal showing that the line tested is free for connection in which latter event the operator will remove the first plug and insert the second plug thereafter proceeding to depress the key 68 or G9, etc. individual to the wanted station and otherwise proceeding as above described. The audible busy test manifestation is due tothe fact that the plug being tested, being connected with the busy hne, has connection with battery traceable from the grounded! battery 28, the lower intermediate armature switch of relay 98, the alternate Contact of this armature switch, the winding of this relay, thcr lower armature switch of the relay and' its right hand aiternate contact, to

the sleeve of the plug 18 beingr tested. The test circuit continues from the heel ot' the plug being tested, the tip nl the (est plug, the upper intermediate armature switch of relay 98, the normal Contact of this armature switch, the uppermost armature switch o1 relay 95, the normal contact ol this switch. the upper winding of relay Sil. the wiper 110 of the employed switch 1i and the waiting contact engaged by this wiper, the second grounded armature switch to the left ot' the winding o1 relay 75 and its upper contact, to ground., relay being energixed owing to the closure of circuit at switch T1 due to the full depression ol key 115. Relay 91 is energized to establish a circuit traceable from the grounded induced winding 11G, the botiom armature switch ot' relay Jl and its contact. the closed contacts 117 of key 115. the wiper 118 of the switch 19 and its engaged contact` the test coils 11'.) of the op-fr erator`s telephone outlit. to ground. As was previously described. the relay 112 is intermittently energized when the relay 91 is energized so that an intermittent current is passed through the inducing winding 111 which is in primary relation to the second ary coils 131, 116 whereby the calling subscriber as well as the operator have testing current induced in their telephone circuits upon the depression of key 115 while the tip of the testing plug 18 is applied to the sleeve of the plug within the jack of a desired line.

lf the calling subscriber 250 at the south exchange should desire connection with a subscriber whose line extends to the main exchange, the operator will employ an idle link connector extending between a switch Il and a switch (l and having keys 22 associated therewith. The operator will depress the key 22 which is connected with wipers 120, 121, 122 of the switch G1 to be employed which move over waiting contacts forming terminals of trunk lines 141 extending to the main oiice. `When the key 22 individual to-v the wipers 120, 121, 122 is fully depressed switch spring 123 pertaining to this kay22 is closed against its contact by the operation of the bar 124 which carries pins 125 engageable by the plungers of the switches 22, the closure of the spring 123 closing a circuit traceable from ground through the spring 123, the Contact engaged by this spring, the wiper 126 of the associate switch 1%), the waiting contact engaged by this Wiper, the winding of relay 127, to the grounded battery 28. The left hand arma turc switch of relay 127 closes a circuit traceable from ground, said switch, its contact, the winding of relay 128, the relay 76, the left hand armature switch of relay 77, to the grounded battery 28, relay 7 7 having been energized by the calling subscrlber as has been described. A locking circuit 1s estab- 

